button:hover{
  cursor:pointer;
  border: 1px solid #000;
}

.btn4:hover{background-color: rgb(241, 241, 241);
border: 1px solid #cacaca;}

.btn44:hover{background-color: red;
  border: 1px solid red;}

  header:hover .xiala{
    display: block;
    cursor:pointer;
      }